Re: libata and sata?

[Stephen Clark]

John Richard Moser wrote:

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> A while back my distro moved to libata for sata_via.  I was since
> confused; my disk seemed a lot slower, and it looked like DMA was off.
> I'm not sure how SATA works; is it even possible to enable/disable
> 32-bit IO and DMA?  Or are those just on?
>
> sata_via               11524  4
> libata                112660  3 ata_generic,pata_via,sata_via
>
> ~$ sudo hdparm -d1 -c1 -u1 /dev/sda
>
> /dev/sda:
> setting 32-bit IO_support flag to 1
> HDIO_SET_32BIT failed: Invalid argument
> setting unmaskirq to 1 (on)
> HDIO_SET_UNMASKINTR failed: Inappropriate ioctl for device
> setting using_dma to 1 (on)
> HDIO_SET_DMA failed: Inappropriate ioctl for device
> IO_support   =  0 (default 16-bit)
>
> I no longer have two kernels to test through; I can't tell if the speed
> is back or not.  Nothing in dmesg tells me if SATA is using DMA or
> 32-bit IO support though, so I don't know... lack of knowledge over here
> is killing me for troubleshooting this on my own.
>
>  
<snip>

Hi John,

This happened to me with my ICH7 intel chipset which supports sata and ata - my drive was an ide and the performance was like 1.2mb/sec. Someone said boot with combined_mode=libata and it fixed the problem.
Now I get 44mb/sec.

HTH,
Steve
--

"They that give up essential liberty to obtain temporary safety, 
deserve neither liberty nor safety."  (Ben Franklin)

"The course of history shows that as a government grows, liberty 
decreases."  (Thomas Jefferson)



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